Nanoscale radiation transport and clinical beam modeling for gold nanoparticle dose enhanced radiotherapy (GNPT) using X-rays

Zygmanski, Piotr; Sajo, Erno

doi:10.1259/bjr.20150200

Cited by 64 publications

(62 citation statements)

References 74 publications

(137 reference statements)

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“…These observations support the use of CH codes and ∼1 keV transport cutoffs in GNPT scenarios in which energy deposition need not be resolved on nm length scales (40 nm range of 1 keV electron in water) and when self‐absorption of sub‐1 keV electrons within GNPs is relatively unimportant. While use of such CH codes and 1 keV transport cutoffs enhance simulation efficiency, thus making simulations possible with available computing power, some GNPT applications require consideration of electron transport to lower energies and event‐by‐event simulation of electron transport (with various associated challenges). These applications include quantification of energy deposition with ~nm resolution in the immediate vicinity of GNPs toward understanding possible considerable DEF variability on nm length scales …”

Section: Discussionmentioning

confidence: 99%

“…In their recent review article, Zygmanski and Sajo emphasized the importance of multiscale considerations for GNPT. The relevant discussion regarding simulation mainly focused on a two‐stage approach, for example, first calculating a phase space within an efficient macroscopic phantom and then creating a microbeam in a more detailed microscopic phantom (see Ref . and references therein).…”

Section: Discussionmentioning

confidence: 99%

“…However, as seen in Figs. , variations in DEFs with depth may be considerable and of importance for prospective clinical GNPT scenarios; indeed, variations in DEFs with depth may be more considerable than much‐studied variations of DEFs with source energy or gold concentration (see Ref . and references therein).…”

Section: Discussionmentioning

confidence: 99%

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Heterogeneous multiscale Monte Carlo simulations for gold nanoparticle radiosensitization

Martinov

Thomson

2017

Medical Physics

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By combining geometric models of varying complexity on different length scales within a single simulation, the HetMS model can effectively account for both macroscopic and microscopic effects which must both be considered for accurate computation of energy deposition and DEFs for GNPT. Efficiency gains with the HetMS approach enable diverse calculations which would otherwise be prohibitively long. The HetMS model may be extended to diverse scenarios relevant for GNPT, providing further avenues for research and development.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Heterogeneous multiscale Monte Carlo simulations for gold nanoparticle radiosensitization

Martinov

Thomson

2017

Medical Physics

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“…For example, the gold (Z = 79) has much stronger photoelectric effect than that of soft tissues (average Z = 7.4). [31][32][33][34][35][36][37][38][39] Au loaded polymeric nanocapsules [40][41][42][43] Au nanomolecules [40,44,45] Active targeting Au nanoparticles [44,[46][47][48][49][50] Rare earth element Gadolinium oxide; Gd doped carbon dots; Gd doped calcium phosphate [51][52][53][54] Upconversion nanoparticles (e.g. Such electron rearrangement in atom orbits would generate excess energy that released either as fluorescent photons or Auger electrons, the latter of which traveling through much shorter distances (typically ≈10 nm) are able to produce high ionization effects in local areas.…”

Section: Mechanisms Of Radio-sensitization With High-z Elementsmentioning

confidence: 99%

Emerging Nanotechnology and Advanced Materials for Cancer Radiation Therapy

et al. 2017

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Radiation therapy (RT) including external beam radiotherapy (EBRT) and internal radioisotope therapy (RIT) has been widely used for clinical cancer treatment. However, owing to the low radiation absorption of tumors, high doses of ionizing radiations are often needed during RT, leading to severe damages to normal tissues adjacent to tumors. Meanwhile, the RT efficacies are limited by different mechanisms, among which the tumor hypoxia-associated radiation resistance is a well-known one, as there exists hypoxia inside most solid tumors while oxygen is essential to enhance radiation-induced DNA damages. With the development in nanotechnology, there have been great interests in using nanomedicine strategies to enhance radiation responses of tumors. Nanomaterials containing high-Z elements to absorb radiation rays (e.g. X-ray) can act as radio-sensitizers to deposit radiation energy within tumors and promote treatment efficacy. Nanoscale carriers are able to deliver therapeutic radioisotopes into tumors for internal RIT, or chemotherapeutic drugs for synergistically combined chemo-radiotherapy. As uncovered in recent studies, the tumor microenvironment could be modulated by various nanomedicine approaches to overcome hypoxia-associated radiation resistance. Herein, the authors will summarize the applications of nanomedicine for RT cancer treatment, and pay particular attention to the latest development of 'advanced materials' for enhanced cancer RT.

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“…Macroscopic regions with containing nanoparticle agents enhance energy deposition both at macroscopic (tissue/organ) and nanoscopic (cellular) levels (Zygmanski and Sajo 2016, McMahon et al 2011). A full detailed analysis of the dose distribution around AuNP would require nanoscopic voxels and knowledge of location of nanoparticles or nanoparticle clusters with respect to cellular targets (cancer cells or cancer microvasculature.)…”

Section: Discussionmentioning

confidence: 99%

A Monte Carlo study of I-125 prostate brachytherapy with gold nanoparticles: dose enhancement with simultaneous rectal dose sparing via radiation shielding

et al. 2017

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We investigate via Monte Carlo simulations a new 125I brachytherapy treatment technique for High-Risk prostate cancer patients via injection of Au nanoparticle (AuNP) directly into the prostate. The purpose of using the nanoparticles is to increase the therapeutic index via two synergistic effects: enhanced energy deposition within the prostate and simultaneous shielding of organs at risk from radiation escaping from the prostate. Both uniform and non-uniform concentrations of AuNP are studied. The latter are modeled considering the possibility of AuNP diffusion after the injection using brachy needles. We study two extreme cases of coaxial AuNP concentrations: centered on brachy needles and centered half-way between them. Assuming uniform distribution of 30mg/g of AuNP within the prostate, we obtain a dose enhancement larger than a factor of 2 to the prostate. Non-uniform concentration of AuNP ranging from 10mg/g and 66mg/g were studied. The higher the concentration in a given region of the prostate the greater is the enhancement therein. We obtain the highest dose enhancement when the brachytherapy needles are coincident with AuNP injection needles but, at the same time, the regions in the tail are colder (average dose ratio of 0.7). The best enhancement uniformity is obtained with the seeds in the tail of the AuNP distribution. In both uniform and non-uniform cases the urethra and rectum receive less than 1/3 dose compared to an analog treatment without AuNP. Remarkably, employing AuNP not only significantly increases dose to the target but also decreases dose to the neighboring rectum and even urethra, which is embedded within the prostate. These are mutually interdependent effects as more enhancement leads to more shielding and vice-versa. Caution must be paid since cold spot or hot spots may be created if the AuNP concentration versus seed position is not properly distributed respect to the seed locations.

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Nanoscale radiation transport and clinical beam modeling for gold nanoparticle dose enhanced radiotherapy (GNPT) using X-rays

Cited by 64 publications

References 74 publications

Heterogeneous multiscale Monte Carlo simulations for gold nanoparticle radiosensitization

Heterogeneous multiscale Monte Carlo simulations for gold nanoparticle radiosensitization

Emerging Nanotechnology and Advanced Materials for Cancer Radiation Therapy

A Monte Carlo study of I-125 prostate brachytherapy with gold nanoparticles: dose enhancement with simultaneous rectal dose sparing via radiation shielding

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